At the moment walking bridges, pipe bridges and conveyor bridges include a supporting frame and walls, floor and roof that cover the frame. Pipes, walking paths, cables and such are located inside the bridge and require further supporting structures that are used for mounting these to the frame of the bridge. Thus the frame has to support all the weight of the covering structures and effective elements as well as their supporting structures, whereby the supporting frame has to be very strong and heavy. A heavy structure further requires a support to the ground or building structures on short spans. Such a heavy structure is slow to build and expensive due to great amount of building material work needed. The cross section of the bridges is typically square, since it is easiest to construct. This leads to large wind surfaces and heavy loads on the bridge due to wind. On snowy environments snow accumulating on the flat roof of the bridge leads to increased stresses and removing of snow during winter may be required. The bridge requires large area on ground or on a floor because of heavy support stands for which typically A-frames are used. This area cannot be effectively used for other purposes because of supports. Overall, the existing bridge structures are very heavy, large and expensive and material costs are high.